User Guide

At the top of the dialog box, you choose the characteristic
you wish to modify: either the left or right sidebearing, or
the width.
Next, you choose which characters you wish to apply the
changes to. We have found that Selected chars is what we
normally choose. So, you can go to the Font Window, select
just those characters you want to adjust, and then choose
only “Selected chars” in Set Metrics.
Finally, you choose what changes to make. The first line is
for setting absolute values. You can set character’s
attributes equal to those of a different character, or equal to
a specific value. You can then add or subtract either an
absolute value or a percentage. For example, you could set
the left sidebearings of , , and equal to the left sidebearing
of A, plus five percent:
The second line is for relative changes. This line allows you
to increase or decrease the selected attribute by either a
number of em-units, or some percentage.
Important: You can absolutely trash your font metrics in no
time at all with Set Metrics. In software interface design,
there is a trade-off between really powerful commands, and
really safe ones. Since we’re in the advanced section now,
all the commands err on the side of being frighteningly
powerful. For this reason, we advise you to Save (or Save
As) your font before doing lots of Set Metrics commands,
so you can Revert if something doesn’t work out.
Assisted Metrics
Assisted metrics are halfway between completely manual
metrics (Set Width and Set Metrics) and fully automatic
metrics manipulation (Auto Space and Auto Kerning).
Assisted metrics are for those typographers who don’t quite
trust the computer to do all their metrics creation for them,
Fontographer User's Manual
5: Metrics: Spacing and Kerning Page #21